POS0249 SEX DIFFERENCES IN PATIENT-REPORTED OUTCOMES IN AXIAL SPONDYLOARTHRITIS PATIENTS TREATED WITH TUMOR NECROSIS FACTOR INHIBITORS: RESULTS FROM A MULTINATIONAL OBSERVATIONAL COHORT STUDY
Authors: P. Hellamand, M. G. H. Van de Sande, M. T. Nurmohamed, R. Van Vollenhoven, R. Hollick, O. Rotariu, Z. Rotar, K. Pirkmajer, D. Nordström, A. M. Hokkanen, B. Michelsen, T. K. Kvien, B. Glintborg, A. G. Loft, K. Pavelka, J. Zavada, I. Castrejon, L. Otero-Varela, B. Gudbjornsson, O. Palsson, M. Østergaard, M. L. Hetland, J. K. Wallman, D. DI Giuseppe, A. Ciurea, M. J. Nissen, T. Demirci Yildirim, F. Onen, C. Codreanu, C. Mogosan, M. J. Santos, E. Vieira-Sousa, F. Iannone, G. Lapadula, L. Midtbøll Ørnbjerg, J. Twisk, I. Van der Horst-Bruinsma
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Women with axial spondyloarthritis (axSpA) tend to have higher scores on patient-reported outcome measures (PROMs), such as the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and the Bath Ankylosing Spondylitis Functional Index (BASFI), compared to men with the same condition. However, it is not well known whether these sex differences are maintained over time during treatment with tumor necrosis factor inhibitors (TNFi), or which factors can potentially explain these sex-based differences. <h3>Objectives</h3> To examine sex differences in BASDAI and BASFI over time in axSpA patients treated with their first TNFi, and to identify potential factors contributing to observed sex differences. <h3>Methods</h3> Pooled data were collected from biologic-naive axSpA patients initiating their first TNFi in the EuroSpA registries. A three-level linear mixed model structure was employed to analyze sex differences in PROMs (BASDAI and BASFI, scale 0-100) over time (sex*time), accounting for correlations between repeated measurements within subjects and between subjects within countries. Baseline characteristics were explored as potential explanatory variables for observed sex differences over time, and interactions between sex, time, and explanatory variables were analyzed. Univariable analysis was performed by incorporating one explanatory variable at a time, while multivariable analysis was used to investigate the effect of multiple explanatory variables on the regression coefficient of sex*time. Only explanatory variables that affected this regression coefficient by more than 10% in univariable analysis were considered for multivariable analysis. A complete case analysis was performed when data were missing for explanatory variables. <h3>Results</h3> This study analyzed data from 11,753 axSpA patients (37% female) with at least two BASDAI measurements over two years, and from 9,780 patients (38% female) with at least two BASFI measurements over the same period. At baseline, women were older and had higher BASDAI/BASFI scores, while men had higher CRP levels, longer disease duration, and higher HLA-B27 positivity. During the follow-up period, women had significantly higher mean BASDAI scores than men (mean difference 6.05; 95% CI 5.27 to 6.83). Additionally, the differences in BASDAI scores between women and men increased by an average of 0.67 (95% CI 0.04 to 1.29) per year. These findings indicate that the sex differences in BASDAI scores persisted and increased over time. In the univariable analysis of explanatory variables, increased age (-8.9%) and longer disease duration (-4.7%) notably explained the sex differences in the BASDAI scores (Figure 1). However, no explanatory variables were eligible for inclusion in the multivariable analysis. We also observed that the sex differences in BASDAI scores were reduced over time in HLA-B27-positive patients, but increased in those with psoriasis (Figure 1). Although women had slightly higher overall BASFI scores than men (mean difference 3.25; 95% CI 2.32 to 4.19), this difference did not vary by time (β = 0.25; 95% CI -0.36 to 0.86). <h3>Conclusion</h3> Women with axSpA treated with their first TNFi had significantly higher mean BASDAI and BASFI scores compared to men over a two-year follow-up period. The mean difference in BASDAI scores increased slightly over time, and the magnitude of this difference was affected by HLA-B27 positivity (reduced) and psoriasis (increased). Further research is needed to understand the mechanisms behind these sex differences and their clinical implications. <h3>Acknowledgements</h3> The EuroSpA Research Collaboration Network was financially supported by Novartis Pharma AG. Novartis had no influence on the data collection, statistical analyses, abstract preparation, or decision to submit the abstract. <h3>Disclosure of Interests</h3> Pasoon Hellamand Grant/research support from: Research grant from Novartis., Marleen G.H. van de Sande Consultant of: Research grant and/or consulting fee, and/or speaker fee from Eli Lilly, Novartis, UCB, Janssen, Abbvie, Michael T Nurmohamed: None declared, Ronald van Vollenhoven Speakers bureau: AbbVie, AstraZeneca, BMS, Galapagos, GSK, Janssen, Pfizer, and UCB, Consultant of: AbbVie, AstraZeneca, Biogen, BMS, Galapagos, Janssen, Pfizer, and UCB, Grant/research support from: Research support: BMS and UCB, Support for Educational programs (institutional grants): MSD, Novartis, Pfizer, Roche, Sanofi, and UCB, Rosemary Hollick Speakers bureau: Gilead, Eli, and Lilly, Ovidiu Rotariu: None declared, Ziga Rotar Speakers bureau: Abbvie, Novartis, MSD, Medis, Biogen, Eli Lilly, Pfizer, Sanofi, Lek, and Janssen, Consultant of: Abbvie, Novartis, MSD, Medis, Biogen, Eli Lilly, Pfizer, Sanofi, Lek, and Janssen, Katja Pirkmajer Speakers bureau: Abbvie, Novartis, MSD, Medis, Eli Lilly, Pfizer, Lek, and Janssen, Consultant of: Abbvie, Novartis, Medis, Eli Lilly, Pfize, and Boehringer Ingelheim, Dan Nordström Speakers bureau: Novartis, Pfizer, and UCB, Consultant of: Abbvie, BMS, Lilly, MSD, Novartis, Pfizer, Roche, and UCB, Grant/research support from: MSD, Anna-Mari Hokkanen Grant/research support from: MSD, Brigitte Michelsen Grant/research support from: Research grant from Novartis (paid to employer), Tore K. Kvien Speakers bureau: Grünenthal, Sandoz, and UCB, Consultant of: AbbVie, Amgen, Celltrion, Gilead, Novartis, Pfizer, Sandoz, and UCB, Grant/research support from: AbbVie, Amgen, BMS, Galapagos, Novartis, Pfizer, and UCB, Bente Glintborg Grant/research support from: Research grants from Pfizer, Abbvie, BMS, and Sandoz, Anne Gitte Loft Speakers bureau: Speaking and/or consulting fees from AbbVie, Janssen, Lilly, MSD, Novartis, Pfizer, Roche, UCB, Grant/research support from: Research grant from Novartis, Karel Pavelka Speakers bureau: AbbVie, UCB, Pfizer, Eli Lilly, Celltrion, MSD, and Novartis, Consultant of: AbbVie, UCB, Pfizer, Eli Lilly, Celltrion, MSD, and Novartis, Jakub Zavada Speakers bureau: Abbvie, Elli-Lilly, Sandoz, Novartis, Egis, UCB, Sanofi, Astra Zeneca, and Sobi, Isabel Castrejon Speakers bureau: Speaker and/or consultancy fees from BMS, Eli-Lilly, Galapagos, Gilead, Janssen, Novartis, MSD, Pfizer, and GSK, Lucía Otero-Varela: None declared, Björn Gudbjornsson Speakers bureau: Novartis and Nordic Pharma, Consultant of: Novartis, Olafur Palsson: None declared, Mikkel Østergaard Speakers bureau: Abbvie, BMS, Boehringer-Ingelheim, Celgene, Eli-Lilly, Galapagos, Gilead, Hospira, Janssen, MEDAC, Merck, Novartis, Novo, Orion, Pfizer, Regeneron, Roche, Sandoz, Sanofi and UCB, Consultant of: Abbvie, BMS, Boehringer-Ingelheim, Celgene, Eli-Lilly, Galapagos, Gilead, Hospira, Janssen, MEDAC, Merck, Novartis, Novo, Orion, Pfizer, Regeneron, Roche, Sandoz, Sanofi and UCB, Grant/research support from: Abbvie, BMS, Merck, Novartis and UCB, Merete Lund Hetland Speakers bureau: Pfizer, Medac, and Sandoz, Grant/research support from: Research grants from Abbvie, Biogen, BMS, Celltrion, Eli Lilly, Janssen Biologics B.V, Lundbeck Fonden, MSD, Medac, Pfizer, Roche, Samsung Biopies, Sandoz, and Novartis, Johan K Wallman Speakers bureau: AbbVie and Amgen, Grant/research support from: Research support from AbbVie, Amgen, Eli Lilly, Novartis, and Pfizer, Daniela Di Giuseppe: None declared, Adrian Ciurea Speakers bureau: AbbVie and Novartis, Consultant of: AbbVie and Novartis, Michael J. Nissen Speakers bureau: AbbVie, Eli Lilly, Janssens, Novartis, and Pfizer, Consultant of: AbbVie, Eli Lilly, Janssens, Novartis, and Pfizer, Tuba Demirci Yildirim: None declared, Fatos Onen Speakers bureau: AbbVie, Amgen, Celltrion, Lilly, Pfizer, Roche, Novartis, Abdi İbrahim, and UCB, Grant/research support from: Research grant from Pfizer, Catalin Codreanu Speakers bureau: AbbVie, Amgen, Boehringer Ingelheim, Ewopharma, Lilly, Novartis, and Pfizer, Consultant of: AbbVie, Amgen, Boehringer Ingelheim, Ewopharma, Lilly, Novartis, and Pfizer, Corina Mogosan Speakers bureau: Speaker fees from AbbVie, Boehringer Ingelheim, Ewopharma, Lilly, Novartis, and Pfizer, Maria Jose Santos Speakers bureau: Abbvie, AstraZeneca, Lilly, Novartis, and Pfizer, Elsa Vieira-Sousa Speakers bureau: Novartis, Abbvie, MSD, Celgene, and UCB, Grant/research support from: Research grants from MSD, Pfizer, and UCB., Florenzo Iannone Speakers bureau: consulting and/or speaking from Abbvie, Amgen, AstraZeneca, BMS, Galapagos, Janssen, Lilly, MSD, Novartis, Pfizer, Roche, UCB, Giovanni Lapadula: None declared, Lykke Midtbøll Ørnbjerg Grant/research support from: Research grant from Novartis, Jos Twisk: None declared, Irene van der Horst-Bruinsma Speakers bureau: BMS, AbbVie, Pfizer and MSD, Consultant of: Abbvie, UCB, MSD, Novartis and Lilly, Grant/research support from: MSD, Pfizer, AbbVie and UCB.